# How do you find the length of the diagonal of a square in terms of its edge a?

$d = \sqrt{2 {a}^{2}}$

#### Explanation:

According to the Pythegorean Theorem,

${d}^{2} = {a}^{2} + {a}^{2}$

${d}^{2} = 2 {a}^{2}$

$d = \sqrt{2 {a}^{2}}$